From patchwork Mon Apr 11 19:44:52 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergei Trofimovich X-Patchwork-Id: 698701 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id p3BJgbRR026746 for ; Mon, 11 Apr 2011 19:42:37 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755575Ab1DKTmf (ORCPT ); Mon, 11 Apr 2011 15:42:35 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:59698 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755274Ab1DKTme (ORCPT ); Mon, 11 Apr 2011 15:42:34 -0400 Received: by bwz15 with SMTP id 15so4781876bwz.19 for ; Mon, 11 Apr 2011 12:42:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:date:from:to:cc:subject:message-id:in-reply-to :references:x-mailer:mime-version:content-type; bh=DYXVgzQZqSW+21s3QOXYm2ZHqUZv0wqKQLt/O2fd6fE=; b=k8TlzPUtORRqF1A0dpkdSkDBGWZUIPvfM4P8UxpFOXy4QwV4+Q/6KaPjKXj8tPthWP G4uAMurNBS+7Z7MKD7qN/MRNPd/PQkXSrsrn90wEQGRndZyUV8Wqf85ig54HBlsAnJgS QKHPSVt6Qo02oq73fDCl4hFwRQu6moyLRZiLA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:in-reply-to:references:x-mailer :mime-version:content-type; b=SWUKXema1kGEfLCk/gKfTWk2Sx2qSCEd4aryaEvXFgcOzzoz2BwnBrHSvyqvOVVoEX JO81BvFrihW6TL2CjnvQYfYVYxgiOdUQ8HS9/1/nb3UxSnl2sLGGA1hhV0Sjb6fm63w5 1E9vjVPk5OzWVnvUeziLaFqhiDizPOhj/5O0U= Received: by 10.205.36.65 with SMTP id sz1mr3626131bkb.74.1302550952972; Mon, 11 Apr 2011 12:42:32 -0700 (PDT) Received: from sf ([178.120.142.184]) by mx.google.com with ESMTPS id v21sm3405843bkt.11.2011.04.11.12.42.30 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 11 Apr 2011 12:42:31 -0700 (PDT) Date: Mon, 11 Apr 2011 22:44:52 +0300 From: Sergei Trofimovich To: Josef Bacik Cc: chris.mason@oracle.com, linux-btrfs@vger.kernel.org, cwillu Subject: [PATCH v3] Re: btrfs does not work on usermode linux Message-ID: <20110411224452.4a5149da@sf> In-Reply-To: <4DA32055.2030104@redhat.com> References: <20110410133710.0ef34cb6@sf> <20110410184249.483d8d67@sf> <20110410230622.09e965ae@sf> <20110410232403.617c3b7f@sf> <20110410235846.135e801e@sf> <4DA32055.2030104@redhat.com> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.22.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Mon, 11 Apr 2011 19:42:38 +0000 (UTC) Reviewed-by: Josef Bacik From 51602c049c4583fc7b1ef454f630138f12dba70e Mon Sep 17 00:00:00 2001 From: Sergei Trofimovich Date: Sun, 10 Apr 2011 23:19:53 +0300 Subject: [PATCH 1/2] btrfs: properly handle overlapping areas in memmove_extent_buffer MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix data corruption caused by memcpy() usage on overlapping data. I've observed it first when found out usermode linux crash on btrfs. ?all chain is the following: ------------[ cut here ]------------ WARNING: at /home/slyfox/linux-2.6/fs/btrfs/extent_io.c:3900 memcpy_extent_buffer+0x1a5/0x219() Call Trace: 6fa39a58: [<601b495e>] _raw_spin_unlock_irqrestore+0x18/0x1c 6fa39a68: [<60029ad9>] warn_slowpath_common+0x59/0x70 6fa39aa8: [<60029b05>] warn_slowpath_null+0x15/0x17 6fa39ab8: [<600efc97>] memcpy_extent_buffer+0x1a5/0x219 6fa39b48: [<600efd9f>] memmove_extent_buffer+0x94/0x208 6fa39bc8: [<600becbf>] btrfs_del_items+0x214/0x473 6fa39c78: [<600ce1b0>] btrfs_delete_one_dir_name+0x7c/0xda 6fa39cc8: [<600dad6b>] __btrfs_unlink_inode+0xad/0x25d 6fa39d08: [<600d7864>] btrfs_start_transaction+0xe/0x10 6fa39d48: [<600dc9ff>] btrfs_unlink_inode+0x1b/0x3b 6fa39d78: [<600e04bc>] btrfs_unlink+0x70/0xef 6fa39dc8: [<6007f0d0>] vfs_unlink+0x58/0xa3 6fa39df8: [<60080278>] do_unlinkat+0xd4/0x162 6fa39e48: [<600517db>] call_rcu_sched+0xe/0x10 6fa39e58: [<600452a8>] __put_cred+0x58/0x5a 6fa39e78: [<6007446c>] sys_faccessat+0x154/0x166 6fa39ed8: [<60080317>] sys_unlink+0x11/0x13 6fa39ee8: [<60016b80>] handle_syscall+0x58/0x70 6fa39f08: [<60021377>] userspace+0x2d4/0x381 6fa39fc8: [<60014507>] fork_handler+0x62/0x69 ---[ end trace 70b0ca2ef0266b93 ]--- http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg09302.html Signed-off-by: Sergei Trofimovich --- fs/btrfs/extent_io.c | 14 +++++++++++--- 1 files changed, 11 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 20ddb28..2655aef 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3885,6 +3885,12 @@ static void move_pages(struct page *dst_page, struct page *src_page, kunmap_atomic(dst_kaddr, KM_USER0); } +static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len) +{ + unsigned long distance = (src > dst) ? src - dst : dst - src; + return distance < len; +} + static void copy_pages(struct page *dst_page, struct page *src_page, unsigned long dst_off, unsigned long src_off, unsigned long len) @@ -3892,10 +3898,12 @@ static void copy_pages(struct page *dst_page, struct page *src_page, char *dst_kaddr = kmap_atomic(dst_page, KM_USER0); char *src_kaddr; - if (dst_page != src_page) + if (dst_page != src_page) { src_kaddr = kmap_atomic(src_page, KM_USER1); - else + } else { src_kaddr = dst_kaddr; + WARN_ON(areas_overlap(src_off, dst_off, len)); + } memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len); kunmap_atomic(dst_kaddr, KM_USER0); @@ -3970,7 +3978,7 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, "len %lu len %lu\n", dst_offset, len, dst->len); BUG_ON(1); } - if (dst_offset < src_offset) { + if (!areas_overlap(src_offset, dst_offset, len)) { memcpy_extent_buffer(dst, dst_offset, src_offset, len); return; } -- 1.7.3.4